Horror/Thriller published around 2006-2009, with a short series of about 6 numbers and letters in title, yellow cover.

[Kristin]

I can't remember specific plot details, but it was really scary, and I'd like to read it again.

[Jo]

Hi Kristin … maybe NOS4A2 by Joe Hill? Although that was published later than your time period.

[Kristin]

Hi Jo, I came across that title earlier, but it's a different book. Thanks for the suggestion though!

[Jo]

Ah no worries!