Cam sensor crankshift sensor

[Mikestaz5]

I HAVE A 2002 Volvo s60 non turbo my car turns over but not fully starting changed spark plugs flushed transmission fluid changed oil I also changed cam sensor crankshaft sensor and car still not working it just turns over I saw online it says I have to clear the codes in order for them to work but I don't think that's the issue because my mechanic says you don't need to install software... Is this true Volvo fans can you please help me out I spent both time and money lost my morning job because if this issue anybody fix this issue?????