problems upgrading??

hey, i used to have limewire on my old computer, then i upgraded it and it told me to restart my computer which i did, then when it started up again i could log on (barely) and when i did the only thing that would open was limewire, and my computer would be frozen (the only thing i could use was limewire, i couldnt click on anything else), because of this i had to reboot my computer because it simply wouldnt work (after a while it stopped letting me use even limewire)!! Im not sure if this was caused by limewire or not, but i was wondering it any one had any similar problems, because i have recently got a new computer and i am hesitant to download limewire again, im not sure if it is safe to download!! any feedback would be appreciated!!! Thanks!