EURO FEARS: Elections in Greece on Sunday are the start of a critical two weeks in Europe that have investors uneasy about whether the eurozone will begin unraveling, sinking stock markets.

MARKET POSSIBILITIES: Experts say a "relief rally" could occur in global markets if Greek voters don't support the anti-reform Syriza party group. But a worst-case scenario -- Greece taking steps to exit the 17-nation eurozone, followed by Spain and Italy -- might send stocks on an extended plunge.

CAUTION ADVISED: Experts advise investors not to abandon the market or change their strategy because of the crisis. But those who will need to tap stock accounts in the next year or two may want to reduce the percentage of stock funds in their 401(k) accounts.