Treo 650 buttons not working

My treo 650 is starting to wear out. The enter button, the space bar, and now the damn “zero” button don’t work anymore. I’d like to know if I can get them working again, before shelling out for a new phone. Any advice?

Don’t know about fixing it, but I got a Treo650 off Ebay for a fairly reasonable price compared to a new unlocked one (in the States; they may be cheaper in Taiwan). Might be a semi-solution.