excel virus, bug?

[windy1]

Something wierd going on. Entering a number into an existing spreadsheets results in that value divided by 100. Checking cell formats are set at numeric or general makes no difference.

Drag an existing cell value to an empty cell, and it keeps its previous value. But hit F2 and type 45 and the cell shows 0.45.

No macros in use

Open new blank spreadsheet, pick any cell, key 65 and it appears as 0.65

Using up to date NAV which virus checks every spreadsheet file when opened. Done a virus scan and its clean. Been to Google and no virus like this?. Symantec knowledge base returns nothing in Excel search. Micorsoft support likewise.

Anyone any ideas what's going on with my excel?

[Tonic Please]

Re-installing office is a good start. You won't loose any work either.

Or this from a M$ search:

In Excel, the appearance of a number is separate from the number that is stored in the cell. In most circumstances, although it appears a number is rounding, only the display of the number is rounded. Calculations use the actual number stored the cell, not the number as it is displayed. You can change the display of numbers on the Number tab of the Format Cells dialog box (Format menu, Cells command).