need help

[Mr. Burns]

we had a server crash a month or so ago, and off and on the site is sluggish, like accessing it thru dialup, for all our members, i am pretty sure it could be the way we replaced it in the new VPS the server people gave us, we copied it from the backup, and recreated the database, however with the old database as server files not dumps as normal, we deleted the server files for the database, and replaced them with the server files from the backup and we have repaired checked the db every day and it still has issues, no errors site runs fine with the exception of the slowness from time to time. i have tried everything i can think of to bring us back to normal speeds.