Doug, there is a difference between upgrade and planned obsolescennce - especially from a Marxist point of view. Upgrade is an increase in the use-value, whereas planned obsolescence is an increase in the exchange value (thus the profit marging) of a product.
If you think about it, PC is designed to maximize its planned-obsolescenceabilty (and rent of copy rights) at the expense of its functionality. A function-optimized machine would have all its software, from the operating system to application permanently stored on a chip - so when you turn your machine, it is instantly operational (instead of dragging you through rentier-occupied zones aka BIOS, DOS, and WINDOWS) and the storage medium (disk) generated error are virtually eliminated. Moreover, you a have a fully functional machine without any room for planned obsoles.. err "upgrades" - in the same way as you may have a 1965 chevy which is not exactly a model of safety and efficiency - but it still runs without the necessity of buying "upgrades" every couple of months.
The separation of "hardware" and "software" created all kinds of technical problems (standardization, the chance of error) - but has one gigantic "advantage" from the monopoly capitalism point of view - it enables capitalist to control products they sold through mere exercise of their property rights. From a purely engineering point of view, an XT machine is fully operational and its functionality is comparable to the super-duper Pentium Mega-bullshit machine i.e. it does the job it was designed for. In the same way, a 1965 chevy is nearly as functional as 1999 mercedes - it provides transportation at a comparable level of personal comfort.
However, you cannot use an otherwise functional XT anymore, because the rentier class (Microsoft and kindred human excrement) crippled its use-value through re-designing copy-righted software. This is tantamount to posting signs prohibiting vehicles older than two or three years from entering a roadway - to force you to buy newer models and discrad perfectly functional older ones.
Computer industry is the most vicious case of monoploy capitalism invented to date, property rights ueber alles (from efficiency to technological progress) the wired idiots extolling the market-schmarket ideology nothwithstanding. That is an empirical fact. Th equestion - is there the knell of this form of capitalist expropriation within reach, and if so, what is it, - or we should brace for the reign of the wired rentier class for many year to come?
FC, as our friend the Unabomber used to say (albeit you can do many things with them, except fucking).
wojtek
PS. As to the problem described by Michael, Windows stores certain information about installed software in the registry files. If something gets deleted without altering the corresponding registry entry then windows may still "think" that the deleted program or its parts are present and tries to open them. That might cause the problem described by Michael. There is a registry editor that can be opened by typing regedit in the run dialog box, but how to edit the proper item in this pile of manure is beyond me (perhaps a call to the MS Office tech support may be helpful).
Otherwise, going ballistic (i.e. reformating the hard drive and reinstalling everything from CD rom or installation disks) may help.