I'm having some strange fluctuations with my USB ports. My mouse, for instance, is moving in a jerky manner and pausing, eventually stopping altogether (I can fix this by reinserting into USB) Some sockets are worse than others for the mouse issue. The mouse works fine on another PCs. Occasionally my PC gets hit with a BSoD when it hits the desktop. It's intermittant though so I've lived with it. I suspect my PSU is not up to the job, is what I have described symptomatic of this? Thanks. AMD X2 3800 Abit KN9-S SATA Hitachi 80GB Deskstar 7200 RPM SATA DVD/CDRW Combo SoundBlaster 4.1 D Nvidia Gforce 7600 GS Floppy disk drive IDE WD Cavier 30GB 7200 RPM A lot of hardware installed here.

"I suspect my PSU is not up to the job" You make the statement, then post zero info about the PSU. What is the make/model, wattage, amperage specs? Why are you using a USB mouse...is it necessary? Do you have an adapter so that you can plug into the PS/2 mouse port? If so, try it. "And that's the fishing line, because Sharkboy said so!"

Yes, my bad. I wanted to edit some details about my PSU earlier. My PSU is an el cheapo. The rails are, 3.3v = 20A, 5V = 30A +12V 20A,. It's a ColorsIT brand,like the case, it came together, as I recall the lot cost about $40/£23.

It's 400w (or so it says!)

It's definitely a cheapie & appears to be a 350W unit, not 400W: http://www.colors-it.com.cn/03_prod... I kinda doubt it's affecting the USB though. How many USB devices do you have connected? And you didn't answer my other question...why are you using a USB mouse rather than PS/2? The mouse pointer problem is probably software related. "And that's the fishing line, because Sharkboy said so!"

Yes, as for PS2 it is probably a better option . Trouble is, that the mice at the local store are all USB, PS/2 seems hard to find. Perhaps those silly OEM's have phased them out like they did to floppy disk drives? I have 5 USB sockets filled, only 2 are in use and the rest are used by things that are switched off, printers, camera to pc etc. Mouse and Keyboard are both active ususally. You mentioned software, but the mouse is PnP. It could be that an old mouse driver I installed is conflicting, but I deleted this. Can you suggest a good option? Appreciated.

I would suggest disconnecting all the other USB devices and see if you still have problems. It sounds to me like the motherboard might be having a problem supplying enough current to the USB devices. Some will draw current even when off.