Would my computer crash? if...?

Yes it should be ok. As you have now got decent ram why not upgrade your hard drive? Western Digital make a 80 Gb IDE drive (ribbon connected) see link. You can also clone your old drive contents to your new drive with Seagate's DiscWizard. So you will keep all programs including the operating system, programs and files. The software is free from Seagate and is legal and above board. It only works with one computer which obviates pirating, see second link.