Enter Key not working on X200s

[novice82]

Dear Members,

I'm running Vista - Home Premium(SP2) on a thinkpad X200s.

I installed Microsoft Security essentials(MES) yesterday.Although everything was working well for sometime, the "Enter" key suddenly stopped working. I've tried un-installing MES, but still can't get the Enter key to work. Actually, i'm not even sure if its a H/w or S/w problem.

Can I somehow configure any Shortcuts to get some other key working as the "enter" key in the interim ?

I'm hoping someone would have come across a similar issue in the past and can offer me some suggestions.

Thanks,

Kris