I would stick to Webroot Spysweeper but it makes my system slow,this program also runs slow,sluggish,may be for inadequate RAM resource :-
So my question is which are the next most effective,reliable and trustworthy?
Pls give me a ranking of anti-spywares in terms of reliability,trust and effectiveness. 
The antispywares which I have seen being recommended by most of the users in Comodo Forums is
Superantispyware (SAS) and Malware Bytes Antimalware (MBAM)
These are free programs (paid versions also available) with on demand scanner. Both are very good antispywares with regular defintion updates.
I recommended Ad-Aware free and IoBit security 360 (Both Realtime select only one.)