Wierd prob?

Hi all,
just recently after a full format when installing games i get crc errors and the game cant install,
I have posted on here with the question before and i was told to disable Ultra Dma Mode on my drives and i did.
But now even with pio mode enabled i get crc errors on some game installs and i also get crc errors when trying to unzip large files?
Surely this can only be 1 of 2 things either my motherboard is going or my hdd.

I have replaced all the ide cbles in the pc just incase it was a dodgey connection, but the problem still occures.
Also during loading of games i will sometimes get textures not loaded or some files missing.

I also sometimes get errors like opera (My browser) has to shut down, occasional blue screens and recently windows explorer has occured a serious error and must shut down, to which i have to reboot?

I have checked for any virus etc etc i have pc cillin and zone alarm as my firewall.

My pc seems to run fine sometimes and then badly on other days? Im at a loss as to what it can be? Plz help

Cheers for ur replies in advance

You refer to your error as crc errors, but do you get any messages referring to these crc errors that point to a specific reason? Check your "event viewer" in "Performance" "Admistration tools", in the control panel. Look for red x's in a circle. These will give you a clue as to what's happening on your computer.

In my event viewer i get-
Error code 000000d1, parameter1 80069010, parameter2 00000002, parameter3 00000000, parameter4 f8938e6f.

that is the error discription. Im lost???

0x000000D1 or DRIVER_IRQL_NOT_LESS_OR_EQUAL

1. This is one of the most common Stop errors. The error typically occurs when a driver tries to access an improper memory address. Check for unsigned drivers, and be especially suspicious of recently installed or updated antivirus programs, disk utilities, and backup programs, which may install a faulty file-system filter driver.

2. Stop 0xD1 messages can occur after installing faulty drivers or system services. If a driver is listed by name, disable, remove, or roll back that driver to confirm that this resolves the error. If so, contact the manufacturer about a possible update. Using updated software is especially important for backup programs, multimedia applications, antivirus scanners, DVD playback, and CD mastering tools.