Oh, I don't know.. If you have a shell acount in a unix box and can get in it, just play around in there... you know learn about shell scripting and learn the command line commands. Man files are your freinds... Putty.exe is a great win32 ssh/telnet/rsh program...
You may try that cywgin thing...
If you don't what to reinstall everything and go with a full fledged linux distro there are a couple alternatives:
IF you want a real raw authentic-feeling Unix experiance you can just try using Zipslack.. It's avaiable from slackware.com and will install in any Fat32 partition... just read and follow the directions carefully and you can boot into it... It only takes about 100megs of space and you won't have to worry about repartitioning your harddrive.... The downside is no nice graphical interface or any niceties. It's a brute minimal linux version.. If ya figure out what your doing you can install X windows on it at the price of about 256 megs of extra diskspace... To bad it won't work if you got a NTFS formatted harddrive.
If you have a nice internet connection and have access to a cd burner, you can use a live cd. These are linux-on-a-cd, and will run completely off of the CDrom drive.. these come with all the nice gui stuff, too.
THe one I like is SuSE's live eval 8.1 cd... This is a made to show off their up and coming 8.1 realese, but it's still kinda beta software, so there are a couple bugs.. Real nice kde interface. all the bells and whistles.. has about a 75%-85% chance of configuring itself and setting itself up with no user intervention. This can be a real "cushy" OS. But it's Linux! which in reality is no more different to Unix then SystemV-based Unix is to BSD-based Unix...
Another eval cd that is highly recommended is Knoppix. It's a debian-based Linux distro. A little bit more daunting to a newb, but it is still realy nice and very usefull, very much more so than the SuSE eval..
You can get both from
www.linuxiso.org