Hey,

Had exacatly the same problem... solved by (in windows):

Control Panel
Power Plans / Change Power Settings (OS dependant)
Change Advanced Power Settings
+ USB Settings
+ USB Selective Suspend Setting
DISABLE
Apply

Basically, my power setting (on a desktop, not latop) was suspsending power to USB. Disable that feature and volia, I have power!!

Cheers

Thanks, by disabling selective suspending I am able to charge now while using USB Storage mode. I still have issues when I select PC Suite mode (does not charge and does not connect with the PC), but I think that is related with a driver and should go to another thread on this forum.

By the way, I had to change that setting using the registry (see below) since the option you mention was not available in Windows XP.

Thanks for the help!!!
----
This procedure describes how to modify the following registry setting:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\USB
Entry: DisableSelectiveSuspend
Type: DWORD
Value: 1 disables selective suspend mode. 0 enables selective suspend mode.
Notes

* This procedure may reduce the battery life on a portable computer.
* This setting affects all USB host controller drivers in the system. If the value of the DisableSelectiveSuspend registry entry is set to 1, selective suspend mode is turned off. Additionally, the Allow the computer to turn off this device to save power check box does not appear on the Power Management tab for the USB root hub.

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es
3. On the Edit menu, point to New, and then click Key.
4. Type USB for the name of the subkey, and then press ENTER.
5. Click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\USB
6. On the Edit menu, point to New, and then click DWORD Value.
7. Type DisableSelectiveSuspend for the name of the DWORD, and then press ENTER.
8. Right-click DisableSelectiveSuspend, and then click Modify.
9. In the Value data box, type 1, and then click OK.
10. Exit Registry Editor.

My phone came down with a stubborn case of "not charging. insufficient power".

It was from a school computers USB that I have charged from before, and I tried different USB spots on the computer and they still didn't work. I started to wonder "maybe my usb port is about to die..." I found a second computer, and a few tries later it started charging again... phew...

This is very true. You might have a look at what applications are running on your N900 on the moment your try to charge it from a low current source such as a PC USB port.
Full CPU power being used on the N900 might be pulling more energy from your battery than it can suck from the charging source.

I found that an older Nokia 800mA wall outlet charger doesn't deliver enough juice when Transmission is verifying files (CPU at 1150Mhz / ideal) to prevent the battery from being depleted in time.

On that moment the only option is to use the 1200(?)mA Nokia N900 wall outlet charger.

Yes, but my N900 tells me this with a different message.
Says something about "The Phone is using more Power than the Charger delivers. Use original charger"

Why is the N900 following those USB Guidelines so strict? Ive seen USB devices doing whatever they like, ive seen USB Ports on my powered Hub going offline (the HUB switched the port offline, not the device connected to it) because the device connected pulled too much power.
Even modern, brand labled devices are often using more power than allowed by the specs (most USB-HDDs wich can be powered via USB, for example)

But the N900 doesnt do that. It even negotiates the power it may take with the Computer. (It has to do this, according to specs. But the mentioned USB-Drives usually dont do this. it would prevent booting from them, though)
I mean, usually its a good thing if a Vendor followes specs, but "someone" should develop an app to override these settings *g*

My phone shows insufficient power when i connect to any computer as well as not charging when i connect the standard wall charger. but the microusb port is firmly in place.

any one have an idea as to what could be the problem?

i guess there is a problem with the USB Driver on our laptops coz it worked fine on my old laptop..

so i will uninstall all the universal serial bus and then reinstall i hope it works.. will update later

I don't know if this will help anyone but I never had this problem until I installed VMware on my windows 7 , and then my n900 was not charging and displaying the 'not charging. insufficient power' message. so I knew it was something to do with VMware.

the way I fixed this problem was to disable the 'VMware USB Arbitration Service' by opening the msconfig tool and unticking the 'VMware USB Arbitration Service' under Services Tap,

Damn. I've been trying to figure it out for the past 2 hours and it turned to be out this damn service.

I tried the device on my friends laptop that also have VMWare and this service is running and the N900 charged just fine. Maybe our VMware versions are different.

However, thanks a lot for the information man.

Man... thank you. That definitely fixed it.