It can be installed on a new PC, but you'll need to phone to MS Activation service (they should have a free number for this) to get a new license code or to reset the old one).
Are you sure you need MS Excel? Did you try Calc from the OpenOffice suite? That's free and without any activation issues surely.
We need Microsoft Excel for our home business. We do not need anything else but Excel. I have found the standalone program for sale for around $65. I see reading the details it can only be installed on one computer. Which is fine because we only needed on one computer. What I am wondering is what happens when I replace the computer or something. Am I not going to be able to reinstall the program? I am wondering if I would be better off paying the money to get the whole Microsoft office program that I can install three times. I just hate to spend the money to buy programs that I do not need. I am looking forward to your advice.