|I agree with ijack that it's almost definitely 32-bit.|
You can find out yourself by opening System Information (Start > Run > type msinfo32), viewing the Summary, and looking at the System Type. If it says x86, it's 32-bit. If it says x64, it's 64-bit.
Apologies if I don't respond to your reply immediately. I don't check this site daily, but you're welcome to PM me as a reminder.