Being refused visas in the past should not count against you. As long as everything is in order with your current application and you supply all the correct documents and evidence, you should get your visa. If however you decide to tell them lies which are subsequently found out, you will almost certainly be refused a visa.
Many of the girls on here have applied and been refused visit visas before they applied and were granted fiancee or spouse visas.
Cheers,
Iain.