Friday's advance secures gains in a week otherwise characterized by a lack of forward progress.
Rising crude prices keep a lid on stocks amid expectations for a strong payroll report Friday.
Crude's midday surge erases any positive tidings generated by the Fed chairman.
OPEC's latest comments and some sell-side bullishness pave the way for solid gains.
Stocks stumble as a biotech scare rattles markets and inflation fears send yields higher.