Roel, as a avid Skype user myself for quite some time, I've not suffered any kind of computer performance problems whatsoever. I suspect that adware, spyware, or a virus may be your culprit, not Skype.

Roel, which specific Ad-Spyware program(s) are you currently running?

Interestingly enough, I've discovered that relying on one Adware-Spyware program alone not effective at catching all ad & spyware, as each program often catches ad-spyware missed by the other ad-spyware programs. For this reason, in addition to keeping Norton AntiVirus running in auto protect mode, I run ALL the following adware spyware software programs, and (so far) haven't suffered computer performance slowdown problems:

* SpySweeper: http://www.webroot.com/products/spysweeper/?WRSID=0d0127810ebe5f2d9b561c902b812c5e

* Microsoft AntiSpyware: http://www.microsoft.com/athome/security/spyware/software/default.mspx

* Ad-Aware PLUS: http://www.lavasoftusa.com/software/adaware/

* Spybot: http://www.download.com/Spybot-Search-Destroy/3000-8022_4-10289035.html

Scott