I was using Trillian, but then I tried that Pidgin, it was the best of the bunch, but it still hung me up a bit. This weekend (if I can find the time) I'm planning to do a backup and reformat of my computer and possibly add some RAM.
I think something is causing a bit of a software conflict. There's other tell-tale signs of problems, and as far as Kaspersy is concerned it's not a virus. But for some reason any IM software makes everything worse.
-Boot into safe mode w/ networking (press f8 before windows to get there)
-Download and run "TFC" by OTL (google OTL TFC and you will find it)
-Delete old system restore points by disabling system restore, then re-enable.
-Lower amount of disk space system restore can use to around 6%
-Run "cleanmgr", as it will find some things TFC missed, as well as compress old files, potentially freeing up a lot of disk space which could improve performance. Make sure you check all available boxes that show potential to free up space.
-Download and run "superantispyware portable" scanner. Doesn't need installed...just run the .exe and do a full scan.
-Disable Kapersky's real-time scanner, firewall, etc
-Download and run "combofix". (easy enough to find on google)
-Download, install, and run Piriform's "ccleaner". Run it's disk cleanup as well as registry tool.
-Re-boot, re-enable kapersky
I bet your computer will be running better if u do all this.
Could also disable some visual features, and/or unneeded start-up items and windows services to improve performance. Also, make sure your page file is set properly.
NOTE: Make sure you know all your logins/passwords for any websites, as TFC will wipe out everything in your cache including saved passwords, etc.
If your computer is old/slow, I'd consider doing away w/ Kapersky, even though it's one of the best AV's out there. Comprehensive security suites tend to really bog down old/slow systems, and some of the free ones (avast is my current favorite) work just as good. I use free Avast, and Comodo's standalone software firewall. Add in the periodic scan with superantispyware portable, and/or malwarebytes antimalware and you will be fine.
Feel free to PM or ICQ me if you have any questions. I am an IT field tech, so sadly, I do this stuff for a living.