Mouse jitters when using mic

Hi folks,

I'm having trouble with my Windows 7 rig. I've been searching through here and haven;t quite found a fitting topic to post under.

Using my computer seems fine most of the time, but when I load up Skype and use my Samson CU1 mic my Logitech MX1000 mouse becomes unresponsive, that't not to say it doesn't work, it just lags.
I have two of the same mice and when I swap them it continues to happen. When I quit Skype it sometimes continues, like tonight when I recorded the call I tried to edit the audio and had to give up as the mouse was just impossible to use.
I've reinstalled Windows 7 a few times over the last few months and the problem has persisted.

A friend suggested that it might be my USB hub as I have a few things plugged in. The Mic, mouse, keyboard, printer, scanner, Android phone, Windows Mobile phone, external USB Sata hard drive dock, webcam - thats all I can think of right now.
My PSU is a 650w and I have a Radeon 5870, 3 Sata drives internally and a bunch of fans blowing.

Could I be running out of power? Should I up upgrade to a 850w?