Is there a way to open my turbotax 2017 *.tax2017 file with my 2018 turbotax online version as my computer with turbotax2017 on it crashed and is no longer accessible

No, the 2017.tax income tax file can't be opened in 2018 TurboTax. However, you can transfer the 2017.tax file so the permanent information can carry over into 2018. 

See When transferring a .tax file, what information carries over to my return?

can I see my 2017 tax

 

You can log into TurboTax if you used the software in the past and log in to obtain the returns. 

 

Accessing prior year returns in TurboTax 

 

The other option is to order copies or transcripts from the IRS. 

 

Requesting copies of prior returns from the IRS