Adobe premiere pro effects applied don’t work

Why the effects all of a sudden stopped being applied ! When I add an effect and do modifications don't work . Nothing happening . Sometimes a red bar shows but doesn't show the effect in progress . I render selection even though can't see what am doing , nothing working . Premiere stopped accepting effects . They are applied but completely null !!! Help please . Thank you . Am new coming from FCPX which has none of this . Thanks

