How do I find Unix Version

I am extremely new here. Someone wants to upgrade off of Unix to Windows 2000 and wants to know if they need to buy new hardware

How do I find out what type of Unix they're using?
How do I find out the current hardware of the system? (Intel, ..etc)

Thanks

uname -a should return info about the OS.
dmesg gives some cryptic hardware info on Solaris

I have found another command that provides better detail on the OS version you are using:
oslevel it will provide this output

> oslevel
4.3.2.0

Whereas on our machine, doing uname -a gives this output:
> uname -a
AIX svcas07 3 4 000145364C00
OS Name Release Version Machine ID

I added the labels underneath for clarity.

For me, doing uname -a gives less accurate info than oslevel does.

Hope this is helpful.

"oslevel" is only available on AIX machines. "uname -a" is available on just about everything.