Excel loading on start up
 

Each time I start up my pc and start Windows I get a message saying that
"Microsoft Excel has encountered a problem and needs to close. We are sorry
for the inconvenience." It asks me if I wish to send an error report.
Then Excel loads but recommends I start up in "safe mode".

Note that I haven't actually tried to start Excel at this stage.

I have checked my Start Up folder and Excel is not there.

Can anyone help? Is it a virus?