Compaq Computer Corp plans to roll out its new low-cost personal computer with the Cyrix Corp processor, aimed at home users in Europe this week. For the problematic German market, the Presario 2110 would give consumers complete multimedia systems with sound, video, facsimile and Internet capabilities for the equivalent of $1,300, a price Compaq did not offer last year when its home personal computer share in Germany declined by more than half.