Problems after upgrade Hardy Heron

[sneg_]

Hi all! I just upgraded to Hardy from Gutsy using apt and I started getting very strange problems. First of all my computer is very slow. When Amarok runs nothing else can, if I try to play movies in MPlayer it turns into a slideshow... I never experienced anything like this on Gutsy. Second of all, if I try to boot with kernel 2.6.24-16/17 the system unexpectedly hangs at random points in time. When I say hang I mean like proper hang, keyboard/mouse stops working. I don't hang if I boot with 2.6.22-14 but it still gives me lag as described above.

I am running the system on a laptop so I suspected it might be something to do with ACPI since I was getting errors regarding DSDT. However, solving the issue didn't help. Grep-ing /var/log also gives these:

sneg@snegolinux:~$ egrep ".*May 30.*error" /var/log/*
/var/log/kern.log:May 30 16:44:38 snegolinux kernel: [4.272000] usb 1-1: device not accepting address 2, error -71
/var/log/kern.log:May 30 18:08:57 snegolinux kernel: [13.700838] usb 1-1: device not accepting address 2, error -71
/var/log/syslog:May 30 18:08:57 snegolinux kernel: [13.700838] usb 1-1: device not accepting address 2, error -71
/var/log/syslog.0:May 30 16:44:38 snegolinux kernel: [4.272000] usb 1-1: device not accepting address 2, error -71

Not sure what they mean or whether they can cause crashes.

Anyway, I am very new to Linux so I don't really know what else I can diagnose to find a possible problem. I would appreciate some help in sorting this out (without distro reinstall if possible).