ATA controller slow down

Last week my computer slowed down dramatically.
-Tranfering 4.3GB of file took over 25 minutes
-HD tune showed 2.2mb/s read and write speed. Before the major slow down, hd-tune is getting 50mb/s+ from each of my two maxtor harddrives
-DVD-RW can only read and write at 1x
-Every program lags
-took 20 minutes boot live cd ubuntu 7.04 from dvd-rw which is very unusual. It used to load under 3 minutes.

These were the problems which i found out after the slow down
-Only the 1st ATA 133 channel works (supporting only 2 drives at 2.2mb/s~ bandwidth). The 2nd channel does not detect anything at all. It stopped working all of a sudden.
-integrated graphic card shows up image, but the image has pink colour as if the D-sub connecton is broken. But when i switched to a discret graphic card, everything was ok.
-The system sometimes dosn't detect ram on the 2nd bank. So sometimes i would only have 512mb of ram instead of the usual 1GB of ram.

Is it normal for a chipset to fail abruptly like this without any warning? Is there any way to fix this issue other than buying a new motherboard?

I have SIS northbridge and southbridge. I think both Northbridge and southbridge are acting weird. There are no fans on the chipsets. They're not overheating. I've already cleared bios a few times to make sure it's not incorrect setting.

I wouldn't start looking for a motherboard for this machine. The CPU is soldered to the motherboard thus i cannot take it off and reuse it.