Excel problem ... With Windows XP Home.

I have 3 PCs with Office 2000 loaded on all.

Two are working okay, whilst the other is giving me problems.

PC 1&2. If I type the number 1 2 or 3 etc, it shows correctly in the cell as 1 2 or 3 or whatever I type.

PC 3. If I type the number 1 2 or 3 etc, it shows in the cell as 0.01 0.02 or 0.03 which is not what I typed and therefore does not compute in the formula (simple column addition).

The only way to get it to add-up correctly is to add a decimal point after each number is typed, such as 1. 2. 3. etc

No matter how the cells are formatted, whether as "Number, Currency" or even general the problem still occurs.

And it's a pain having to do this all the time.

Any suggestions how to correct this problem please.